Monthly Archives: April 2020

During these unprecedented times with people sheltering in place all over the country, we’ve been asking ourselves a lot of questions. Is it safe to leave the house? When will our kids go back to school? Where am I going to find toilet paper? When will all of this be over?

And perhaps, most unexpectedly—have my neighbors always been this noisy?

With people spending more time at home than ever, individuals living in multifamily housing may now be noticing noise from the neighbors that had previously gone unnoticed. Acoustically speaking, they may be subjected to airborne noise impacts from neighbors that share a wall, floor, or ceiling with them. You now know that your next-door neighbor washes dishes to the oldies every morning, the one below you argues with their seventh grader about schoolwork in the afternoon, and the one above you sits down at 10 p.m. to watch the next installment of Tiger King nightly.

Or, if you have upstairs neighbors, impact noise may be a concern. Perhaps your upstairs neighbor changed their flooring from carpet to hardwood two months ago and it didn’t bother you until now, when it suddenly sounds like there’s a tap dance recital happening overhead while you’re on a conference call.

Both airborne and impact noise in multifamily housing have been regulated by the California Building Code for construction since 1974 using minimum Sound Transmission Class (STC) and Impact Isolation Class (IIC) ratings. A higher rating represents a higher amount of noise reduction from one side of the assembly to the other. The code minimum is STC 50 for airborne noise through common walls or floor/ceiling assemblies, with the added IIC 50 requirement for impact noise through floor/ceiling assemblies. Some Homeowners Associations have regulations that require higher ratings, but all multifamily housing constructed in or after 1974 needs to meet these minimum ratings set by the state.

At this point, you may be thinking that your wall or floor/ceiling in question assuredly does not meet the rating requirements, considering how well you can hear your neighbor’s every move, but unfortunately, code compliance does not equal inaudibility, nor does it mean that the assembly is “soundproof.” Compliance can be determined by either 1) assembly review and assessment by an acoustical consultant, or 2) acoustically testing the assemblies.

An acoustical assembly review is an effective and non-invasive way to review an assembly for rating determination; however, it cannot be accomplished without the review of as-built building plans. These can sometimes be tricky to track down but may be on file with either your Homeowners Association or the offices of your local government. An acoustical consultant can look at the various elements that were included when the assembly was constructed to give an estimate of the ratings.

Testing, on the other hand, requires access to both your unit and your neighbor’s. Testing airborne noise requires the generation of high levels of noise on one side of the assembly while measuring the sound on the other side of the assembly. Impact testing uses a tapping machine that drops small metal cylinders on the floor while noise measurements are performed in the unit below. In both cases, testing is performed and results are calculated using the appropriate ASTM International standards.

In the short-term, some people may find temporary relief with methods other than earplugs (or banging a broom handle on the ceiling). The addition of masking noise can be particularly helpful. A white noise machine or a small indoor fountain can sometimes reduce the noticeability of extraneous noise sources by adding either a benign, inoffensive, or pleasing noise to your home.

If you’re reading this and thinking, “I’ve never heard my neighbors before”… ask yourself, “Am I the noisy one?” In any case, our best advice here is to be considerate, be kind, and stay safe at home! We’ll be back out in the rest of the noisy world soon enough.